3 stage cooling and defrosting system using quick-freezing chamber, freezing chamber, and refrigerating chamber

ABSTRACT

The present invention relates to a system for cooling a quick-freezing chamber at −40 to −30° C., a freezing chamber at −20 to −15° C., a refrigerating chamber at 0 to 5° C., and the like and an energy-saving defrosting system for defrosting the quick-freezing chamber, the freezing chamber, and the refrigerating chamber using condensed waste heat.

TECHNICAL FIELD

The invention relates to a 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber, wherein waste heat energy from condenser is recovered and stored.

More specifically, this invention relates to a 3 stage cooling system and defrosting system wherein waste heat energy from condenser is recovered and stored for defrosting, which comprises a cooling apparatus comprising a compressor for compressing the refrigerant, a condenser for condensing the refrigerant with emitting waste heat energy, an electronic valve for injecting the refrigerant to the 3 stage cooling chamber; a −40˜-30° C. of quick-freezing chamber wherein the refrigerant supplied from condenser is evaporated and remaining refrigerant is recovered to freezing chamber or refrigerating chamber; a −20˜-15° C. of freezing chamber wherein the refrigerant supplied from condenser and/or quick-freezing chamber is evaporated and remaining refrigerant is recovered to refrigerating chamber; and a 0˜5° C. of refrigerating chamber wherein the refrigerant supplied from condenser, quick-freezing chamber and/or freezing chamber is evaporated and evaporated refrigerant is discharged outside of refrigerating chamber.

DESCRIPTION OF PRIOR ART

A cooling system comprises a heat exchanger and a circulating refrigerant for cooling the loading space. 3 stage cooling system of the present invention also applies 4 steps of sequentially repeated cooling cycle containing compression, condensing, expansion and evaporation of refrigerant. Of course, the absorption of evaporation heat energy makes the loading place to be cooled.

The compressor is an apparatus for compressing the refrigerant to be high pressure and high temperature of vapor phase so that compressed vapor phase refrigerant is easily condensed in the condenser. Thermal energy is exchanged while the refrigerant circulates condensation and evaporation cycles. The structure of compressor is designed for compressing the vapor phase refrigerant through piston moving in the cylinder. The vapor phase refrigerant from compressor is condensed to be liquid phase refrigerant with emitting heat energy to the outside of condenser. Further, the condensed liquid phase refrigerant is supplied to evaporator through liquid receiver. The liquid receiver has a role for supplying refrigerant to the evaporator with storage of condensed refrigerant.

In conventional system, for evaporating the condensed refrigerant at lower than −30° C. it is very hard to meet with required low evaporation pressure, because the conventional 1 step compressor cannot supply the required low evaporation pressure due to its lower condensed refrigerant pressure. Therefore, 2 step or 3 step compressor affording highly compressed vapor phase refrigerant has been required to supply the required low evaporation pressure.

If we explain 2 step of compression as an example of multi-step of compression, the lower step of compression makes the refrigerant to be medium pressure of vapor phase refrigerant and obtained medium pressure of vapor phase refrigerant is injected into the inter-cooler. Then, the refrigerant is cooled until the saturation temperature corresponding to medium pressure. Finally, the higher step of compression makes the refrigerant to be high pressure and high temperature of vapor phase refrigerant before transferring to condenser.

Further, through passing the expansion valve, the condensed high pressure and high temperature of refrigerant is expanded and converted to low pressure and low temperature of refrigerant. In the course of evaporating the refrigerant, it absorbs evaporation heat energy surrounded evaporator, which causes the loading space to be cooled as well as the generation of frost outside of evaporator.

The surface temperature of evaporator absorbing outside heat energy becomes to be lower than ambient air temperature, while the ambient air outside of evaporator is relatively high humid. Accordingly, the condensed moisture from ambient humid air is converted to be a frost, which clings to the surface of evaporator. Finally, the thickness of frost become increasing by lapse of time, which causes the inefficiency of heat exchange around evaporator as well as the excess consumption of electronic energy.

On the other hand, in Korean Patent Early Publication No. 10-2006-5303 ‘Rapid freezing and refrigerating storage apparatus of Rubus coreanus’, the inventors of present invention have disclosed a freezing chamber and a refrigerating chamber for storage of Rubus coreanus equipping unit coolers inside of chambers.

In this patent disclosure, a freezing chamber having freezing chamber unit cooler inside and a refrigerating chamber having refrigerating chamber unit cooler inside for the storage of Rubus coreanus have been disclosed. More specifically, the cooling and storage system of Rubus coreanus comprising a multi-step compressor for compressing refrigerant, an air cooling condenser for condensing refrigerant, a high pressure liquid receiver, a panel shape of inter-cooler for cooling the refrigerant, a freezing chamber and a refrigerating chamber has been disclosed. In the freezing chamber, the condensed refrigerant is evaporated in the freezing chamber unit cooler to be −40˜-20° C. of inside chamber, while remaining refrigerant from freezing chamber is evaporated in the refrigerating chamber unit cooler to be −15˜5° C. of inside chamber in the freezing chamber.

Further, in this patent disclosure, only cooling system for −40˜-20° C. of freezing chamber and −15˜-5° C. of refrigerating chamber with multi-step compressor and circulation of refrigerant has been disclosed. However, there has been no disclosure about 3 stage cooling system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber of the present invention. Of course, there has been also no disclosure about the supply, the circulation and/or the recovery of refrigerant for maximizing the heat efficiency, such as, transfer, absorption and/or emission of heat energy from refrigerant.

Therefore, the inventor of present invention has tried to develop a 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber, wherein the optimal supply, circulation and/or recovery of refrigerant is applied as well as the waste heat energy from condenser is recovered and stored for defrosting quick-freezing chamber, freezing chamber and refrigerating chamber.

Finally, the inventors of present invention have developed a 3 stage cooling and defrosting system wherein waste heat energy from condenser is recovered and stored for defrosting, which comprises a cooling apparatus comprising a multi-step of compressor for compressing the refrigerant, a condenser emitting waste heat energy, an electronic valve for injecting the refrigerant; a −40˜-30° C. of quick-freezing chamber wherein the refrigerant supplied from condenser is evaporated and remaining refrigerant is recovered to freezing chamber or refrigerating chamber; a −20˜-15° C. of freezing chamber wherein the refrigerant supplied from condenser and/or quick-freezing chamber is evaporated and remaining refrigerant is recovered to refrigerating chamber; and a 0˜5° C. of refrigerating chamber wherein the refrigerant supplied from condenser, quick-freezing chamber and/or freezing chamber is evaporated and evaporated refrigerant is discharged

Problem to be Solved

The problem to be solved is to develop a 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber. More specifically, this is to develop a 3 stage cooling and defrosting system wherein waste heat energy from condenser is recovered and stored for defrosting, which comprises a cooling apparatus comprising a multi-step of compressor for compressing the refrigerant, a condenser emitting waste heat energy, an electronic valve for injecting the refrigerant; a −40˜-30° C. of quick-freezing chamber wherein the refrigerant supplied from condenser is evaporated and remaining refrigerant is recovered to freezing chamber; a −20˜-15° C. of freezing chamber wherein the refrigerant supplied from condenser and/or quick-freezing chamber is evaporated and remaining refrigerant is recovered to refrigerating chamber; and a 0˜5° C. of refrigerating chamber wherein the refrigerant supplied from condenser, quick-freezing chamber and/or freezing chamber is evaporated and evaporated refrigerant is discharged.

Means for Solving the Problem

The object of present invention is to provide a 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber, comprising the 3 stage cooling steps of: 1) −40˜-30° C. of quick-freezing step in quick-freezing chamber, wherein the liquid phase refrigerant sprayed from electronic valve (S3) away from condenser after 2 step compression is evaporated and then the ultra lower temperature of liquid phase refrigerant sequentially is further evaporated until the quick-freezing chamber to be lower than −40° C.; 2) −20˜-15° C. of freezing step in freezing chamber, wherein the refrigerant injected from electronic valve (R1) after recovery from quick-freezing chamber is evaporated after closing electronic valve (V1), and the liquid phase refrigerant sprayed from electronic valve (S2) away from condenser can be further evaporated until the freezing chamber to be −20° C. and 3) 0˜5° C. of refrigerating step in refrigerating chamber, wherein the refrigerant injected from electronic valve (R2) after recovery from quick-freezing chamber and/or freezing chamber is evaporated after closing electronic valve (V2), and the liquid phase refrigerant sprayed from electronic valve (S1) away from condenser can be further evaporated until the refrigerating chamber to be 0° C.

Further, the structure of 3 stage cooling system comprises 1) a multi (2) step compressor comprising a lower step compressor for compressing the vapor phase refrigerant to be medium pressure, an inter-cooler for cooling the refrigerant until the saturation temperature corresponding to medium pressure, and a higher step compressor for compressing the cooled refrigerant to be high pressure and high temperature of vapor phase refrigerant; 2) a condenser for condensing the high pressure and high temperature vapor phase refrigerant from compressor to be liquid phase refrigerant; 3) a quick-freezing evaporator for quick-freezing the chamber using liquid phase refrigerant from condenser; 4) a freezing evaporator for freezing the chamber using liquid phase refrigerant from condenser and/or vapor phase refrigerant recovered from quick-freezing chamber; and 5) a refrigerating evaporator for refrigerating the chamber using liquid phase refrigerant from condenser and/or vapor phase refrigerant recovered from quick-freezing chamber and/or freezing chamber.

Further, said 3 stage cooling system comprising the steps of: 1) −40˜-30° C. of quick-freezing step in quick-freezing chamber, wherein the low temperature of liquid phase refrigerant sprayed from expansion valve (1) passing through electronic valve (a, b) away from condenser after 2 step compression is evaporated until the quick-freezing chamber to be −25° C. and then the ultra lower temperature of liquid phase refrigerant sprayed from expansion valve (2) sequentially is evaporated until the quick-freezing chamber to be lower than −40° C. 2) −20˜-15° C. of freezing step in freezing chamber, wherein the vapor phase refrigerant injected from electronic valve (7) after recovery from quick-freezing chamber is evaporated, and the low temperature of liquid phase refrigerant sprayed from electronic valve (4) passing through electronic valve (c, d) away from condenser is evaporated until the freezing chamber to be −20° C. and 3) 0˜5° C. of refrigerating step in refrigerating chamber, wherein the vapor phase refrigerant injected from electronic valve (8) after recovery from quick-freezing chamber and/or freezing chamber is evaporated, and the low temperature of liquid phase refrigerant sprayed from electronic valve (e, f) away from condenser is evaporated until the refrigerating chamber to be 0° C.

Further, if the temperature of recovered refrigerant from quick-freezing chamber is higher than −20° C. in second freezing step, the liquid phase refrigerant is injected and evaporated for freezing the chamber after opening electronic valve (c) and manual valve (e), while the liquid phase refrigerant is injected and evaporated for refrigerating the chamber after opening electronic valve (e) and manual valve (5), if the temperature of recovered refrigerant from quick-freezing chamber and/or freezing chamber is higher than 0° C. in third refrigerating step.

Further, upon selecting the normal operation or the defrosting operation by control panel; in normal operation, the cooling system is operated and circulated after suspending circulation pump [5] for defrosting with closing check valve (V7), wherein the wasted heat energy emitted from external condenser [2] is received and stored in the waste heat storage tank [4], after heat exchange between external condenser and brine until the temperature of brine becomes to be 30˜40° C. while in defrosting operation, the defrosting system is started and operated by restarting and operating circulation pump [5] with opening check valve (V7) after suspending the operation of cooling system, wherein 30˜40° C. of heated brine stored in the waste heat storage tank [4] is supplied into brine pipe for removing a frost present outer surface of evaporator [3] and 4˜15° C. of brine is circulated and recovered to waste heat storage tank [4].

If the temperature of brine in waste heat storage tank [4] is lower than 40° C. in normal operation, another route of 3 way valve [6] is open for supplying the heat energy from high temperature of vapor refrigerant directly to the waste heat storage tank [4] by closing normal circulation route of vapor phase refrigerant, while 3 way valve [6] is open for normal circulation route, if the temperature of brine in waste heat storage tank [4] is higher than 40° C. 3 way valve [6] is open for ordinary route.

Advantageous Effect

The advantageous effect of present invention is to provide a 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber. Further, the present invention is provide a 3 stage cooling and defrosting system wherein waste heat energy from condenser is recovered and stored for defrosting, which comprises a cooling apparatus comprising a multi-step of compressor for compressing the refrigerant, a condenser emitting waste heat energy, an electronic valve for injecting the refrigerant; a −40˜-30° C. of quick-freezing chamber wherein the refrigerant supplied from condenser is evaporated and remaining refrigerant is recovered to freezing chamber; a −20˜-15° C. of freezing chamber wherein the refrigerant supplied from condenser and/or quick-freezing chamber is evaporated and remaining refrigerant is recovered to refrigerating chamber; and a 0˜5° C. of refrigerating chamber wherein the refrigerant supplied from condenser, quick-freezing chamber and/or freezing chamber is evaporated and evaporated refrigerant is discharged.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of the whole configuration of 3 stage cooling and defrosting system comprising −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber of the present invention, wherein waste heat energy from condenser is used for defrosting quick-freezing chamber, freezing chamber and refrigerating chamber

FIG. 2 is a schematic diagram for illustrating the multi-step compression of 3 stage cooling system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention.

As shown in FIG. 2, multi (2) step compressor of present invention comprises a lower step compressor for compressing the vapor phase refrigerant to be medium pressure, an inter-cooler for cooling the refrigerant until the saturation temperature corresponding to medium pressure, and a higher step compressor for compressing the cooled refrigerant to be high pressure and high temperature of vapor phase refrigerant.

FIG. 3 is a schematic diagram for illustrating the supply, circulation and recovery of refrigerant in 3 stage cooling system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention.

As shown in FIG. 3, 3 stage cooling system of the present invention starts from the first quick-freezing step for −40˜-30° C. of quick-freezing chamber, wherein the low temperature of liquid phase refrigerant injected from expansion valve (1) passing through electronic valve (a, b) away from condenser after 2 step compression is expanded and evaporated until the quick-freezing chamber to be −25° C. and then the ultra lower temperature of liquid phase refrigerant injected from expansion valve (2) sequentially is expanded and evaporated until the quick-freezing chamber to be lower than −40° C.

Subsequently, the second freezing step for −20˜-15° C. of freezing chamber follows. The vapor phase refrigerant injected from electronic valve (7) after recovery from quick-freezing chamber is evaporated. If the recovered vapor phase refrigerant is not sufficient for freezing chamber, the low temperature of liquid phase refrigerant supplied from electronic valve (4) passing through electronic valve (c, d) away from condenser is expanded and evaporated until the freezing chamber to be −20° C.

Finally, third refrigerating step for 0˜5° C. of refrigerating chamber follows. The vapor phase refrigerant injected from electronic valve (8) after recovery from quick-freezing chamber and/or freezing chamber is evaporated. If the recovered vapor phase refrigerant is not sufficient for refrigerating chamber, the low temperature of liquid phase refrigerant supplied from electronic valve (6) passing through electronic valve (e, f) away from away from condenser is expanded and evaporated until the refrigerating chamber to be 0° C.

FIG. 4 is a schematic diagram for illustrating the supply, circulation and recovery of refrigerant of quick-freezing chamber unit cooler (evaporator), freezing chamber unit cooler (evaporator) and refrigerating chamber unit cooler (evaporator) of the present invention.

Through the main pipe, low temperature liquid phase refrigerant is sequentially supplied to quick-freezing chamber unit cooler, freezing chamber unit cooler and refrigerating chamber unit cooler. Recovered vapor refrigerant from quick-freezing chamber unit cooler is supplied to freezing chamber unit cooler after closing electronic valve (V1) and recovered vapor refrigerant from freezing chamber unit cooler is supplied to refrigerating chamber unit cooler after closing electronic valve (V2). Electronic valve or manual valve can be used for its convenience.

FIG. 5A shows the normal operation of 3 stage cooling and defrosting system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention.

In normal operation, the cooling system is operated and circulated after suspending circulation pump [5] used for defrosting with closing check valve (V7). Then, the wasted heat energy emitted from external condenser [2] is received and stored in the waste heat storage tank [4] until the temperature of brine becomes to be 30˜40° C. upon heat exchanging between external condenser and brine.

FIG. 5B shows the defrosting operation of 3 stage cooling and defrosting system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention. The waste heat energy from condenser is used for defrosting quick-freezing chamber, freezing chamber and refrigerating chamber.

In defrosting operation, the defrosting system is started and operated by restarting and operating circulation pump [5] with opening check valve (V7) after suspending the operation of cooling system. 30˜40° C. of heated brine stored in the waste heat storage tank [4] is supplied into brine pipe for removing a frost present outer surface of evaporator [3] and brine is circulated and recovered to waste heat storage tank [4].

PREFERRED EMBODIMENT OF INVENTION

The invention relates to a 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber, comprising the 3 stage cooling steps of: 1) −40˜-30° C. of quick-freezing step in quick-freezing chamber, wherein the liquid phase refrigerant sprayed from electronic valve (S3) away from condenser after 2 step compression is evaporated and then the ultra lower temperature of liquid phase refrigerant sequentially is further evaporated until the quick-freezing chamber to be lower than −40° C.; 2) −20˜-15° C. of freezing step in freezing chamber, wherein the refrigerant injected from electronic valve (R1) after recovery from quick-freezing chamber is evaporated after closing electronic valve (V1), and the liquid phase refrigerant sprayed from electronic valve (S2) away from condenser can be further evaporated until the freezing chamber to be −20° C. and 3) 0˜5° C. of refrigerating step in refrigerating chamber, wherein the refrigerant injected from electronic valve (R2) after recovery from quick-freezing chamber and/or freezing chamber is evaporated after closing electronic valve (V2), and the liquid phase refrigerant sprayed from electronic valve (S1) away from condenser can be further evaporated until the refrigerating chamber to be 0° C.

Further, normal operation and defrosting operation is selected by control panel. In normal operation, the cooling system is operated and circulated after suspending circulation pump [5] for defrosting with closing check valve (V7), wherein the wasted heat energy emitted from external condenser [2] is received and stored in the waste heat storage tank [4], after heat exchange between external condenser and brine until the temperature of brine becomes to be 30˜40° C. Further, in defrosting operation, the defrosting system is started and operated by restarting and operating circulation pump [5] with opening check valve (V7) after suspending the operation of cooling system, wherein 30˜40° C. of heated brine stored in the waste heat storage tank [4] is supplied into brine pipe for removing a frost present outer surface of evaporator [3] and 4˜15° C. of brine is circulated and recovered to waste heat storage tank [4].

The present invention can be explained more specifically in reference to attached drawings.

FIG. 1 is a schematic diagram of the whole configuration of 3 stage cooling and defrosting system comprising −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber of the present invention, wherein waste heat energy from condenser is used for defrosting quick-freezing chamber, freezing chamber and refrigerating chamber

The cooling system for cooling quick-freezing chamber, freezing chamber and refrigerating chamber of the present invention can be explained as follows. The compressed vapor phase refrigerant by the compressor can be easily condensed in the condenser. In the course of condensing the compressed vapor phase refrigerant, the waste heat is emitted outside of condenser, which is transferred and stored in waste heat storage tank. Further, high temperature of condensed refrigerant is transferred and sequentially supplied to quick-freezing cooler, freezing cooler and refrigerating cooler, where the refrigerant is evaporated with absorption of surrounded heat energy in quick-freezing chamber, freezing chamber and refrigerating chamber. Finally, vapor phase refrigerant from evaporator is recovered to compressor and the cooling cycle will be repeated.

On the other hand, the defrosting system for defrosting quick-freezing cooler, freezing cooler and refrigerating cooler of the present invention can be explained as follows. The brine is heated and stored in waste heat storage tank upon receiving the waste heat energy emitted from condenser. Further, the heated brine is sequentially supplied into the defroster for quick-freezing cooler, freezing cooler and refrigerating cooler. After defrosting, the brine is recover to waste heat storage tank.

FIG. 2 is a schematic diagram for illustrating the multi-step compression of 3 stage cooling system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention.

As shown in FIG. 2, multi (2) step compressor of present invention comprises a lower step compressor for compressing the vapor phase refrigerant to be medium pressure, an inter-cooler for cooling the refrigerant until the saturation temperature corresponding to medium pressure, and a higher step compressor for compressing the cooled refrigerant to be high pressure and high temperature of vapor phase refrigerant

Further, the structure of 3 stage cooling system can be explained as follows. The multi (2) step compressor comprises a lower step compressor for compressing the vapor phase refrigerant to be medium pressure, an inter-cooler for cooling the refrigerant until the saturation temperature corresponding to medium pressure, and a higher step compressor for compressing the cooled refrigerant to be high pressure and high temperature of vapor phase refrigerant. The condenser condenses the high pressure and high temperature vapor phase refrigerant from compressor to be liquid phase refrigerant. The quick-freezing evaporator quickly-freezes the chamber using liquid phase refrigerant from condenser. The freezing evaporator freezes the chamber using liquid phase refrigerant from condenser and/or vapor phase refrigerant recovered from quick-freezing chamber. Finally, the refrigerating evaporator refrigerates the chamber using liquid phase refrigerant from condenser and/or vapor phase refrigerant recovered from quick-freezing chamber and/or freezing chamber.

FIG. 3 is a schematic diagram for illustrating the supply, circulation and recovery of refrigerant in 3 stage cooling system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention.

As shown in FIG. 3, 3 stage cooling system of the present invention starts from the first quick-freezing step for −40˜-30° C. of quick-freezing chamber, wherein the low temperature of liquid phase refrigerant injected from expansion valve (1) passing through electronic valve (a, b) away from condenser after 2 step compression is expanded and evaporated until the quick-freezing chamber to be −25° C. and then the ultra lower temperature of liquid phase refrigerant injected from expansion valve (2) sequentially is expanded and evaporated until the quick-freezing chamber to be lower than −40° C.

Subsequently, the second freezing step for −20˜-15° C. of freezing chamber follows. The vapor phase refrigerant injected from electronic valve (7) after recovery from quick-freezing chamber is evaporated. If the recovered vapor phase refrigerant is not sufficient for freezing chamber, the low temperature of liquid phase refrigerant supplied from electronic valve (4) passing through electronic valve (c, d) away from condenser is expanded and evaporated until the freezing chamber to be −20° C.

Finally, third refrigerating step for 0˜5° C. of refrigerating chamber follows. The vapor phase refrigerant injected from electronic valve (8) after recovery from quick-freezing chamber and/or freezing chamber is evaporated. If the recovered vapor phase refrigerant is not sufficient for refrigerating chamber, the low temperature of liquid phase refrigerant supplied from electronic valve (6) passing through electronic valve (e, f) away from away from condenser is expanded and evaporated until the refrigerating chamber to be 0° C.

On the other hand, if the temperature of recovered refrigerant from quick-freezing chamber is higher than −20° C. in the second freezing step, the liquid phase refrigerant is sprayed and evaporated for freezing the chamber after opening electronic valve (c) and manual valve (e).

Further, if the temperature of recovered refrigerant from quick-freezing chamber and/or freezing chamber is higher than 0° C. in third refrigerating step, the liquid phase refrigerant is sprayed and evaporated for refrigerating the chamber after opening electronic valve (e) and manual valve (5).

FIG. 4 is a schematic diagram for illustrating the supply, circulation and recovery of refrigerant of quick-freezing chamber unit cooler (evaporator), freezing chamber unit cooler (evaporator) and refrigerating chamber unit cooler (evaporator) of the present invention.

As shown in FIG. 4, through the main pipe, low temperature liquid phase refrigerant is sequentially supplied to quick-freezing chamber unit cooler, freezing chamber unit cooler and refrigerating chamber unit cooler. Recovered vapor refrigerant from quick-freezing chamber unit cooler is supplied to freezing chamber unit cooler after closing electronic valve (V1) and recovered vapor refrigerant from freezing chamber unit cooler is supplied to refrigerating chamber unit cooler after closing electronic valve (V2). Electronic valve or manual valve can be used for its convenience.

FIG. 5A shows the normal operation of 3 stage cooling and defrosting system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention.

In normal operation, the cooling system is operated and circulated after suspending circulation pump [5] used for defrosting with closing check valve (V7). Then, the wasted heat energy emitted from external condenser [2] is received and stored in the waste heat storage tank [4] until the temperature of brine becomes to be 30˜40° C. upon heat exchanging between external condenser and brine.

If the temperature of brine in waste heat storage tank [4] is lower than 40° C. in normal operation, another route of 3 way valve [6] is open for supplying the heat energy from high temperature of vapor refrigerant directly to the waste heat storage tank [4] by closing normal circulation route of vapor phase refrigerant. On the other hand, if the temperature of brine in waste heat storage tank [4] is higher than 40° C. 3 way valve [6] is open for normal circulation route.

FIG. 5B shows the defrosting operation of 3 stage cooling and defrosting system comprising quick-freezing chamber, freezing chamber, and refrigerating chamber of the present invention. The waste heat energy from condenser is used for defrosting quick-freezing chamber, freezing chamber and refrigerating chamber.

In defrosting operation, the defrosting system is started and operated by restarting and operating circulation pump [5] with opening check valve (V7) after suspending the operation of cooling system. 30˜40° C. of heated brine stored in the waste heat storage tank [4] is supplied into brine pipe for removing a frost present outer surface of evaporator [3] and brine is circulated and recovered to waste heat storage tank [4].

REFERENCE NUMERAL

-   -   a, b: electronic valve for supplying liquid refrigerant to         quick-freezing chamber     -   c, d: electronic valve for supplying liquid refrigerant to         freezing chamber     -   e, f: electronic valve for supplying refrigerant to         refrigerating chamber     -   1: expansion valve in quick-freezing chamber for cooling to −25°         C.     -   2: expansion valve in quick-freezing chamber for cooling to −40°         C.     -   3: manual valve for spaying refrigerant to freezing chamber     -   4: expansion valve for freezing chamber     -   5: manual valve for spaying refrigerant to refrigerating chamber     -   6: expansion valve for refrigerating chamber     -   7: electronic valve for supplying vapor refrigerant to freezing         chamber     -   8: electronic valve for supplying vapor refrigerant to         refrigerating chamber     -   9, 10, 11, 12: Blocking electronic valves     -   S1: electronic valve for supplying refrigerant to refrigerating         chamber     -   S2: electronic valve for supplying liquid refrigerant to         freezing chamber     -   S3: electronic valve for supplying liquid refrigerant to         quick-freezing chamber     -   S8: condenser external temperature sensor     -   S9: stored brine temperature sensor     -   S10: waste heat exchanger temperature sensor     -   S11: cooler temperature sensor     -   S12: frost detection sense sensor     -   S13: supplied brine temperature sensor     -   V1: electronic valve for vapor refrigerant recovery     -   V2: electronic valve for vapor refrigerant recovery     -   V7: check valve     -   R1: electronic valve for vapor refrigerant supply to freezing         chamber     -   R2: electronic valve for vapor refrigerant supply to         refrigerating chamber 

1. A 3 stage cooling and energy saving defrosting system using −40˜-30° C. of quick-freezing chamber, −20˜-15° C. of freezing chamber, and 0˜5° C. of refrigerating chamber, comprising the 3 stage cooling steps of: 1) −40˜-30° C. of quick-freezing step in quick-freezing chamber, wherein the liquid phase refrigerant sprayed from electronic valve (S3) away from condenser after 2 step compression is evaporated and then the ultra lower temperature of liquid phase refrigerant sequentially is further evaporated until the quick-freezing chamber to be lower than −40° C.; 2) −20˜-15° C. of freezing step in freezing chamber, wherein the refrigerant injected from electronic valve (R1) after recovery from quick-freezing chamber is evaporated after closing electronic valve (V1), and the liquid phase refrigerant sprayed from electronic valve (S2) away from condenser can be further evaporated until the freezing chamber to be −20° C.; and 3) 0˜5° C. of refrigerating step in refrigerating chamber, wherein the refrigerant injected from electronic valve (R2) after recovery from quick-freezing chamber and/or freezing chamber is evaporated after closing electronic valve (V2), and the liquid phase refrigerant sprayed from electronic valve (S1) away from condenser can be further evaporated until the refrigerating chamber to be 0° C.
 2. The 3 stage cooling and defrosting system according to claim 1, wherein the structure of 3 stage cooling system comprises 1) a multi (2) step compressor comprising a lower step compressor for compressing the vapor phase refrigerant to be medium pressure, an inter-cooler for cooling the refrigerant until the saturation temperature corresponding to medium pressure, and a higher step compressor for compressing the cooled refrigerant to be high pressure and high temperature of vapor phase refrigerant; 2) a condenser for condensing the high pressure and high temperature vapor phase refrigerant from compressor to be liquid phase refrigerant; 3) a quick-freezing evaporator for quick-freezing the chamber using liquid phase refrigerant from condenser; 4) a freezing evaporator for freezing the chamber using liquid phase refrigerant from condenser and/or vapor phase refrigerant recovered from quick-freezing chamber; and 5) a refrigerating evaporator for refrigerating the chamber using liquid phase refrigerant from condenser and/or vapor phase refrigerant recovered from quick-freezing chamber and/or freezing chamber.
 3. The 3 stage cooling and defrosting system according to claim 1, wherein said 3 stage cooling system comprising the steps of: 1) −40˜-30° C. of quick-freezing step in quick-freezing chamber, wherein the low temperature of liquid phase refrigerant sprayed from expansion valve (1) passing through electronic valve (a, b) away from condenser after 2 step compression is evaporated until the quick-freezing chamber to be −25° C., and then the ultra lower temperature of liquid phase refrigerant sprayed from expansion valve (2) sequentially is evaporated until the quick-freezing chamber to be lower than −40° C.; 2) −20˜-15° C. of freezing step in freezing chamber, wherein the vapor phase refrigerant injected from electronic valve (7) after recovery from quick-freezing chamber is evaporated, and the low temperature of liquid phase refrigerant sprayed from electronic valve (4) passing through electronic valve (c, d) away from condenser is evaporated until the freezing chamber to be −20° C.; and 3) 0˜5° C. of refrigerating step in refrigerating chamber, wherein the vapor phase refrigerant injected from electronic valve (8) after recovery from quick-freezing chamber and/or freezing chamber is evaporated, and the low temperature of liquid phase refrigerant sprayed from electronic valve (e, f) away from condenser is evaporated until the refrigerating chamber to be 0° C.
 4. The 3 stage cooling and defrosting system according to claim 3, wherein if the temperature of recovered refrigerant from quick-freezing chamber is higher than −20° C. in 2nd freezing step, the liquid phase refrigerant is injected and evaporated for freezing the chamber after opening electronic valve (c) and manual valve (e), while the liquid phase refrigerant is injected and evaporated for refrigerating the chamber after opening electronic valve (e) and manual valve (5), if the temperature of recovered refrigerant from quick-freezing chamber and/or freezing chamber is higher than 0° C. in 3rd refrigerating step.
 5. The 3 stage cooling and defrosting system according to claim 1, wherein upon selecting the normal operation or the defrosting operation by control panel; in normal operation, the cooling system is operated and circulated after suspending circulation pump [5] for defrosting with closing check valve (V7), wherein the wasted heat energy emitted from external condenser [2] is received and stored in the waste heat storage tank [4], after heat exchange between external condenser and brine until the temperature of brine becomes to be 30˜40° C., while in defrosting operation, the defrosting system is started and operated by restarting and operating circulation pump [5] with opening check valve (V7) after suspending the operation of cooling system, wherein 30˜40° C. of heated brine stored in the waste heat storage tank [4] is supplied into brine pipe for removing a frost present outer surface of evaporator [3] and 4˜15° C. of brine is circulated and recovered to waste heat storage tank [4].
 6. The 3 stage cooling and defrosting system according to claim 5, wherein if the temperature of brine in waste heat storage tank [4] is lower than 40° C. in normal operation, another route of 3 way valve [6] is open for supplying the heat energy from high temperature of vapor refrigerant directly to the waste heat storage tank [4] by closing normal circulation route of vapor phase refrigerant, while 3 way valve [6] is open for normal circulation route, if the temperature of brine in waste heat storage tank [4] is higher than 40° C., 3 way valve [6] is open for ordinary route.
 7. The 3 stage cooling and defrosting system according to claim 2, wherein said 3 stage cooling system comprises the steps of: 1) −40˜-30° C. of quick-freezing step in quick-freezing chamber, wherein the low temperature of liquid phase refrigerant sprayed from expansion valve (1) passing through electronic valve (a, b) away from condenser after 2 step compression is evaporated until the quick-freezing chamber to be −25° C., and then the ultra lower temperature of liquid phase refrigerant sprayed from expansion valve (2) sequentially is evaporated until the quick-freezing chamber to be lower than −40° C.; 2) −20˜-15° C. of freezing step in freezing chamber, wherein the vapor phase refrigerant injected from electronic valve (7) after recovery from quick-freezing chamber is evaporated, and the low temperature of liquid phase refrigerant sprayed from electronic valve (4) passing through electronic valve (c, d) away from condenser is evaporated until the freezing chamber to be −20° C.; and 3) 0˜5° C. of refrigerating step in refrigerating chamber, wherein the vapor phase refrigerant injected from electronic valve (8) after recovery from quick-freezing chamber and/or freezing chamber is evaporated, and the low temperature of liquid phase refrigerant sprayed from electronic valve (e, f) away from condenser is evaporated until the refrigerating chamber to be 0° C. 